In recent years, attention has been drawn to marine animal oils as useful foodstuffs for both human and animal consumption. These oils often contain Omega-three fatty acids, particularly EPA and DHA. Omega-three fatty acids are those in which doublebond unsaturation occurs at, and no closer than, the third carbon atom from the end of the acid molecule. Other Omega-three fatty acids include linolenic acid and docosapentaenoic acid (DPA). Linolenic acid is a component of soybeans, linseed and some green, leafy vegetables. In the detailed description below, this invention will be discussed in connection with preferred embodiments where Omega-three acid-containing marine animal oils are used. However, other sources of Omega-three fatty acids, e.g., plants, can also be employed.
The scientific literature has recognized that marine animal oils likely have substantial therapeutic value. Such literature includes, e.g., the following articles: (I) Phillipson, B. E., et al., "Reduction of Plasma Lipoproteins and Aproteins By Dietary Fish Oils In Patients With Hypertriglyceridemia", N. Engl. J. Med. 312: 1210-1216 (1985); (II) Nestel, P. J., "Fish Oil Attenuates The Cholesterol Induced Rise In Lipoprotein Cholesterol," Am. J. Clin. Nutr. 43:752-757 (1986); (III) "Marine Lipid Concentrate Improves Plasma Lipid Levels In CHD", Int. Med. News 19:7 (May 15, 1986); and (IV) Harris, W. S., "Health Effects of Omega-Three Fatty Acids", Contemporary Nutrition 10:8, pp. 145-6 (August, 1985). There is evidence that this therapeutic activity is due in large part to the Omega-three fatty acids.
Among the probable therapeutic benefits of consuming Omega-three acid-containing marine animal oils which find support in the scientific literature are: reduced plasma triglycerides, reduced ischemia, and reduced tissue destruction by auto-immune diseases. Aside from these probable therapeutic benefits, marine animal oils are recognized as edible nutrients, and can be beneficially incorporated into foods for both human and animal consumption.
It is known that Omega-three fatty acids such as EPA and DHA are readily oxidized in the presence of light, oxygen, heat, trace minerals and moisture. When oxidized, these fatty acids become discolored, odoriferous, and less therapeutically active.
Conventionally, marine animal oils have been encapsulated in soft elastic capsules which effectively protect the oil under normal storage conditions. Such a product was recently introduced to the commercial market by Squibb under the trade name PROTOCHOL. A similar product, marketed by Warner-Lambert, is sold under the trade name PROMEGA. A third such product, "MAX EPA", is marketed by RP Scherer N.A. These soft elastic gelatin capsule products consist essentially of a consolidated one-gram dose of marine animal oil encased in gelatin.
In contrast, according to a first embodiment where spray-drying is employed, the products of this invention are microspheres, each microsphere containing, on average, several hundred gelatin-encased marine animal oil microdroplets. According to two additional embodiments where a double dispersion beadlet process or a catch-medium process is used, the products of this invention are macrospheres, each macrosphere being similar in structure to a microsphere except for its greater volume and density. Each macrosphere contains, on average, several thousand gelatin-encased marine animal oil microdroplets.
Japanese patent application disclosure (KOKAI) No. SHO 60-49097, issued Mar. 18, 1985, discloses a marine animal oil product which is microencapsulated, the microcoating consisting essentially of casein and saccharides. The products of the Japanese '097 disclosure are said to be stable for one month when stored at about 5.degree. C. away from light, or for one year at about 5.degree. C. if packaged in a container having oxygen- and ultra violet light-barrier properties.
Despite these advances in the art of packaging Omega-three acid-containing marine animal oils to make them storage-stable and suitable for preparation of tableted dosages, as well as for convenient addition into food products for human and animal consumption, further advances are desirable. In particular, further improvements are needed in long term storage-stability, adaptability to compression for tableting, bio-availability (rapidity with which the microdroplets of oil are released from a microemulsified coating versus from a conventional gelatin capsule), and free-flowing dry structure for ease of handling.
It is an object of this invention to provide an improved dry microemulsified Omega-three acid-containing oil product which is stabilized against deterioration, characterized by improved bio-availability, and which may readily be tableted or otherwise incorporated into food products for human and animal consumption.
It is an additional object of this invention to provide a process for producing dry stabilized microemulsified Omega-three acid-containing oil products.
Further objects will be apparent from the discussion below.